let teacher = {
  name: 'kobe',
  weight: 120,
  teach() {
    console.log('basketball');
  },
  eat() {
    this.weight -= 10;
    console.log(this.weight, 'weighttttttttttttttttttt');
  },
};
teacher.teach();
teacher.age = 29;
teacher.drink = function drink() { console.log('i am drinking beer'); }
teacher.drink();
delete teacher.drink;
delete teacher.teach(); // 会执行teach方法。不会删除对象的teach方法
teacher.eat();
teacher.eat();
teacher.eat();
console.log(teacher);


  